The present invention relates generally to a wall framing system for use in assembling multilayer walls having a base layer separated from a secondary layer, and more particularly to an improved wall framing clip, such as may be used to assemble a curtain wall on a building exterior, an area separation wall, or a shaftwall for stairwells, elevator shafts and the like.
Other multilayer wall constructions are known, for example, in U.S. Pat. No. 4,152,878 to Balinski, U.S. Pat. No. 4,408,427 to Zilch, and the U.S. Pat. No. B1-4,353,192 to Pearson, et al., each of which discloses an elongate stud positioned between two layers of gypsum wallboard. Each stud includes an integrally formed wallboard holding portion which serves to retain the wallboard against one face of the stud. The wallboard holding portion defines a pair of opposed channels so that the stud can be positioned at the vertical seam of two adjacent wallboard panels and retain the edges of the panels within the channels. One or more additional layers of the wallboard are fastened, typically by screws, to the opposite face of the stud, thereby creating an air space between the wallboard layers.
Another single piece framing stud for forming fire retardant shaftwalls is disclosed in U.S. Pat. Nos. 3,740,912 and 3,921,346 both to Sauer et al. The Sauer et al. stud requires separate nails or screws to secure both the inner and outer wall panels to the stud.
U.S. Pat. No. 3,553,915 to Passovoy discloses a clip system comprising an elongate multiple piece clip which is removably attached to a C-shaped stud to hold the vertical edges of a pair of adjacent wall panels against the stud. The Passovoy clip is used to assemble wall panels to form area separation or partition walls. The Passovoy clip includes a first snap-on clip member having a hook portion which clips onto the stud. The Passovoy clip further includes a second head member which is matingly received by the clip member so as to define a pair of elongate channels for snugly receiving the vertical edges of the wall panels therein. The Passovoy system apparently requires access to each side of the wall to install the two-piece clips.
U.S. Pat. No. 4,649,689 to Everman et al. discloses a multiple piece clip which is removably attached to a stud for assembling insulation board for roofs. The Everman system requires multiple separate fasteners which clip along the length of a single stud. Each fastener has a bifurcated shank portion which may protrude through the insulation board to engage a support washer installed on the opposite side of the insulation board. The Everman system appears to require access to both sides of the wall to install the washer on one side and the clip on the other.
Another wall framing clip system is disclosed in U.S. Pat. No. 4,578,922 to Wendt. The Wendt system uses a plurality of bent wire clips having sharp impaling ends which are embedded into the side edges of wallboard panels. The wire clips also have a bent spring-tensioned stud receiving portion which clip onto the stud to hold the wallboard in place. A plurality of the wire clips are required along the length of the stud. The Wendt system is viewed as a structurally weaker system, because the wire clips structurally damage the wallboard upon assembly. Furthermore, the Wendt clips grip only a portion of the wallboard thickness to secure the wallboard to the stud, as opposed to gripping the entire thickness of the wallboard.
Other clip systems include the multiple clip system disclosed in U.S. Pat. No. 1,940,933 to Balduf. U.S. Pat. No. 3,238,685 to Emroy discloses a single piece window retaining clip for retaining a window within a metal window frame.
These other wall construction systems suffer from various disadvantages. For example, many require multiple clips to engage each stud used to construct the wall, with each clip requiring extensive labor to be installed. Some of these systems require access to both sides of the wall being constructed, which is undesirable for constructing shaftwalls or exterior curtain walls for buildings without scaffolding. Other one piece systems are disadvantageous because they do not allow flexibility in interchanging the stud size, to accommodate varying interwall spacings as required by various building codes and applications. Also, such one piece systems require the wall retaining portion to be made out of the same heavy gauge of metal as the load bearing stud portion which is subject to a much greater load. Some of the known clip systems leave the edges of two adjoining panels exposed to damage. Others engage the wall panels at isolated spaced apart locations and are inherently weaker in providing structural support for a secondary wall layer supported by the stud to which the clips are attached.
Thus, a need exists for an improved wall framing system for constructing multilayer walls comprising base and secondary layers, such as may be used to form a building exterior curtain wall, an area separation wall, or a shaftwall for a stairwell or an elevator shaft, which is not susceptible to the above limitations and disadvantages.